In the activity described in this article, students will explore how variables in a first-class lever, specifically arm length, position of the fulcrum, and placement of the load, affect the effort needed to lift the load. To begin the lesson, demonstrate to the class how a first-class lever works and review what is meant by the terms fulcrum, effort, and load/resistance. During the demonstration, change the location of the fulcrum and position of the load, but always keep the fulcrum between the effort and load/resistance. Also, demonstrate how to attach a spring scale to the lever to measure the effort used to lift a load, but keep the load and fulcrum in the same place as this is being explained. Wrap a large rubber band around one end of the board and connect the hook of the spring scale to the band. At this point, invite students up to the demonstration area to measure the amount of effort needed to lift a variety of different loads.